This invention relates to a plastic clip comprising a pin and bushing for connecting members such as panels to a body such as a car body.
Plastic clips for connecting a member such as a panel to a body such as a car body are well known. Japanese Unexamined Patent Application No. 8-177824 discloses a pin-and-bushing plastic clip comprising a pin with a head and a shank extending from the head, and a bushing with a flange and a shank extending from the flange. A through-hole is formed in the bushing flange and shank for inserting the pin shank. The pin shank is inserted into the through-hole, and the pin is connected to the bushing with a fixed interval between the pin head and the bushing flange. A hole in a member such as a panel is aligned with a hole in a body such as a car body; the bushing shank is inserted into the aligned holes; the bushing flange is brought into contact with the member; the pin shank is pushed in until the pin head makes contact with the bushing flange; the diameter of the bushing shank expands; and the expanded diameter bushing shank and flange connect the member to the body. A first water-tight seal is situated between the pin head and the bushing flange, and a second water-tight seal is situated between the bushing flange and the member to form a water-tight seal between the pin and the bushing as well as between the bushing and the member.
Japanese Unexamined Utility Model Application No. 6-24220 discloses a plastic screw grommet comprising a flange and a hollow shank. A tapping screw is screwed into the flange hole and hollow shank, thereby expanding the diameter of the shank and attaching the screw grommet to a body such as a car body. In this screw grommet, a special thermoplastic seal washer is situated where the flange comes into contact with the car body. By heat softening the washer, a seal can be formed between the surface of the flange and the surface of the car body.
Japanese Unexamined Utility Model Application No. 63-115907 discloses another plastic screw grommet comprising a flange and a hollow shank. A tapping screw is screwed into a flange hole and the hollow shank, thereby expanding the diameter of the shank and attaching the screw grommet to a body such as a car body. In this screw grommet, too, a soft seal washer is situated where the flange comes into contact with the car body to create a seal between the surface of the flange and the surface of the car body. Opposing edges of the flange have shape-retaining ribs to retain the shape of the flange making contact with the car body even when pressure on the soft seal washer would otherwise deform it.
The pin and bushing type clip described in Japanese Unexamined Patent Application No. 8-177824 has a water tight seal member situated between the pin head and the bushing flange to form a water tight seal between the pin and the bushing. However, if a worker applies too much force when pushing the pin into the bushing, the soft seal member can become deformed and broken. Also, a rebounding force may damage the elasticity of the seal member and reduce the longevity of the water-tight seal.
The plastic screw grommet described in Japanese Unexamined Utility Model Application No. 6-24220 has a special thermoplastic seal washer situated where the flange comes into contact with the car body, and a tight seal is formed between the surface of the flange and the surface of the car body by heat softening the washer. However, this requires a special heat softening process.
The plastic screw grommet described in Japanese Unexamined Utility Model Application No. 63-115907 has shape-retaining ribs on the flange to prevent unstable contact between the soft seal member and the surface of the car body and to retain the shape of the flange and screw grommet itself. While these shape retaining ribs tend to prevent excessive deformation of the seal member, they are not always effective to maintain the sealing function of the seal member.